user/sven/linux.git/include/linux/topology.h, branch leds/HEAD

sched/topology: Rename topology_thread_cpumask() to topology_sibling_cpumask()

2015-05-27T13:22:15Z

Rename topology_thread_cpumask() to topology_sibling_cpumask() for more consistency with scheduler code. Signed-off-by: Bartosz Golaszewski Reviewed-by: Thomas Gleixner Acked-by: Russell King Acked-by: Catalin Marinas Cc: Benoit Cousson Cc: Fenghua Yu Cc: Guenter Roeck Cc: Jean Delvare Cc: Jonathan Corbet Cc: Linus Torvalds Cc: Oleg Drokin Cc: Peter Zijlstra Cc: Rafael J. Wysocki Cc: Russell King Cc: Viresh Kumar Link: http://lkml.kernel.org/r/1432645896-12588-2-git-send-email-bgolaszewski@baylibre.com Signed-off-by: Ingo Molnar

topology: add support for node_to_mem_node() to determine the fallback node

2014-10-10T02:25:51Z

Anton noticed (http://www.spinics.net/lists/linux-mm/msg67489.html) that on ppc LPARs with memoryless nodes, a large amount of memory was consumed by slabs and was marked unreclaimable. He tracked it down to slab deactivations in the SLUB core when we allocate remotely, leading to poor efficiency always when memoryless nodes are present. After much discussion, Joonsoo provided a few patches that help significantly. They don't resolve the problem altogether: - memory hotplug still needs testing, that is when a memoryless node becomes memory-ful, we want to dtrt - there are other reasons for going off-node than memoryless nodes, e.g., fully exhausted local nodes Neither case is resolved with this series, but I don't think that should block their acceptance, as they can be explored/resolved with follow-on patches. The series consists of: [1/3] topology: add support for node_to_mem_node() to determine the fallback node [2/3] slub: fallback to node_to_mem_node() node if allocating on memoryless node - Joonsoo's patches to cache the nearest node with memory for each NUMA node [3/3] Partial revert of 81c98869faa5 (""kthread: ensure locality of task_struct allocations") - At Tejun's request, keep the knowledge of memoryless node fallback to the allocator core. This patch (of 3): We need to determine the fallback node in slub allocator if the allocation target node is memoryless node. Without it, the SLUB wrongly select the node which has no memory and can't use a partial slab, because of node mismatch. Introduced function, node_to_mem_node(X), will return a node Y with memory that has the nearest distance. If X is memoryless node, it will return nearest distance node, but, if X is normal node, it will return itself. We will use this function in following patch to determine the fallback node. Signed-off-by: Joonsoo Kim Signed-off-by: Nishanth Aravamudan Cc: David Rientjes Cc: Han Pingtian Cc: Pekka Enberg Cc: Paul Mackerras Cc: Benjamin Herrenschmidt Cc: Michael Ellerman Cc: Anton Blanchard Cc: Christoph Lameter Cc: Wanpeng Li Cc: Tejun Heo Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

mm: disable zone_reclaim_mode by default

2014-06-04T23:53:59Z

When it was introduced, zone_reclaim_mode made sense as NUMA distances punished and workloads were generally partitioned to fit into a NUMA node. NUMA machines are now common but few of the workloads are NUMA-aware and it's routine to see major performance degradation due to zone_reclaim_mode being enabled but relatively few can identify the problem. Those that require zone_reclaim_mode are likely to be able to detect when it needs to be enabled and tune appropriately so lets have a sensible default for the bulk of users. This patch (of 2): zone_reclaim_mode causes processes to prefer reclaiming memory from local node instead of spilling over to other nodes. This made sense initially when NUMA machines were almost exclusively HPC and the workload was partitioned into nodes. The NUMA penalties were sufficiently high to justify reclaiming the memory. On current machines and workloads it is often the case that zone_reclaim_mode destroys performance but not all users know how to detect this. Favour the common case and disable it by default. Users that are sophisticated enough to know they need zone_reclaim_mode will detect it. Signed-off-by: Mel Gorman Acked-by: Johannes Weiner Reviewed-by: Zhang Yanfei Acked-by: Michal Hocko Reviewed-by: Christoph Lameter Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

sched: Rework sched_domain topology definition

2014-05-07T11:33:49Z

We replace the old way to configure the scheduler topology with a new method which enables a platform to declare additionnal level (if needed). We still have a default topology table definition that can be used by platform that don't want more level than the SMT, MC, CPU and NUMA ones. This table can be overwritten by an arch which either wants to add new level where a load balance make sense like BOOK or powergating level or wants to change the flags configuration of some levels. For each level, we need a function pointer that returns cpumask for each cpu, a function pointer that returns the flags for the level and a name. Only flags that describe topology, can be set by an architecture. The current topology flags are: SD_SHARE_CPUPOWER SD_SHARE_PKG_RESOURCES SD_NUMA SD_ASYM_PACKING Then, each level must be a subset on the next one. The build sequence of the sched_domain will take care of removing useless levels like those with 1 CPU and those with the same CPU span and no more relevant information for load balancing than its children. Signed-off-by: Vincent Guittot Tested-by: Dietmar Eggemann Reviewed-by: Preeti U Murthy Reviewed-by: Dietmar Eggemann Signed-off-by: Peter Zijlstra Cc: Andrew Morton Cc: Benjamin Herrenschmidt Cc: Bjorn Helgaas Cc: Chris Metcalf Cc: Christoph Lameter Cc: David S. Miller Cc: Fenghua Yu Cc: Greg Kroah-Hartman Cc: Hanjun Guo Cc: Heiko Carstens Cc: Jason Low Cc: Linus Torvalds Cc: Martin Schwidefsky Cc: Tony Luck Cc: linux390@de.ibm.com Cc: linux-ia64@vger.kernel.org Cc: linux-s390@vger.kernel.org Link: http://lkml.kernel.org/r/1397209481-28542-2-git-send-email-vincent.guittot@linaro.org Signed-off-by: Ingo Molnar

mm: use raw_cpu ops for determining current NUMA node

2014-04-07T23:36:13Z

With the preempt checking logic for __this_cpu_ops we will get false positives from locations in the code that use numa_node_id. Before the __this_cpu ops where introduced there were no checks for preemption present either. smp_raw_processor_id() was used. See http://www.spinics.net/lists/linux-numa/msg00641.html Therefore we need to use raw_cpu_read here to avoid false postives. Note that this issue has been discussed in prior years. If the process changes nodes after retrieving the current numa node then that is acceptable since most uses of numa_node etc are for optimization and not for correctness. There were suggestions to implement a raw_numa_node_id in order to do preempt checks for numa_node_id as well. But I think we better defer that to another patch since that would mean investigating how numa_node_id() is used throughout the kernel which would increase the scope of this patchset significantly. After all preemption was never checked before when numa_node_id() was used. Some sample traces: __this_cpu_read operation in preemptible [00000000] code: login/1456 caller is __this_cpu_preempt_check+0x2b/0x2d CPU: 0 PID: 1456 Comm: login Not tainted 3.12.0-rc4-cl-00062-g2fe80d3-dirty #185 Call Trace: dump_stack+0x4e/0x82 check_preemption_disabled+0xc5/0xe0 __this_cpu_preempt_check+0x2b/0x2d get_task_policy+0x1d/0x49 get_vma_policy+0x14/0x76 alloc_pages_vma+0x35/0xff handle_mm_fault+0x290/0x73b __do_page_fault+0x3fe/0x44d do_page_fault+0x9/0xc page_fault+0x22/0x30 generic_file_aio_read+0x38e/0x624 do_sync_read+0x54/0x73 vfs_read+0x9d/0x12a SyS_read+0x47/0x7e cstar_dispatch+0x7/0x23 caller is __this_cpu_preempt_check+0x2b/0x2d CPU: 0 PID: 1456 Comm: login Not tainted 3.12.0-rc4-cl-00062-g2fe80d3-dirty #185 Call Trace: dump_stack+0x4e/0x82 check_preemption_disabled+0xc5/0xe0 __this_cpu_preempt_check+0x2b/0x2d alloc_pages_current+0x8f/0xbc __page_cache_alloc+0xb/0xd __do_page_cache_readahead+0xf4/0x219 ra_submit+0x1c/0x20 ondemand_readahead+0x28c/0x2b4 page_cache_sync_readahead+0x38/0x3a generic_file_aio_read+0x261/0x624 do_sync_read+0x54/0x73 vfs_read+0x9d/0x12a SyS_read+0x47/0x7e cstar_dispatch+0x7/0x23 Signed-off-by: Christoph Lameter Acked-by: Ingo Molnar Cc: Alex Shi Cc: Tejun Heo Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

sched/balancing: Periodically decay max cost of idle balance

2013-09-20T10:03:46Z

This patch builds on patch 2 and periodically decays that max value to do idle balancing per sched domain by approximately 1% per second. Also decay the rq's max_idle_balance_cost value. Signed-off-by: Jason Low Signed-off-by: Peter Zijlstra Link: http://lkml.kernel.org/r/1379096813-3032-4-git-send-email-jason.low2@hp.com Signed-off-by: Ingo Molnar

sched/balancing: Consider max cost of idle balance per sched domain

2013-09-20T10:03:44Z

In this patch, we keep track of the max cost we spend doing idle load balancing for each sched domain. If the avg time the CPU remains idle is less then the time we have already spent on idle balancing + the max cost of idle balancing in the sched domain, then we don't continue to attempt the balance. We also keep a per rq variable, max_idle_balance_cost, which keeps track of the max time spent on newidle load balances throughout all its domains so that we can determine the avg_idle's max value. By using the max, we avoid overrunning the average. This further reduces the chance we attempt balancing when the CPU is not idle for longer than the cost to balance. Signed-off-by: Jason Low Signed-off-by: Peter Zijlstra Link: http://lkml.kernel.org/r/1379096813-3032-3-git-send-email-jason.low2@hp.com Signed-off-by: Ingo Molnar

sched: recover SD_WAKE_AFFINE in select_task_rq_fair and code clean up

2012-08-13T17:02:05Z

Since power saving code was removed from sched now, the implement code is out of service in this function, and even pollute other logical. like, 'want_sd' never has chance to be set '0', that remove the effect of SD_WAKE_AFFINE here. So, clean up the obsolete code, includes SD_PREFER_LOCAL. Signed-off-by: Alex Shi Signed-off-by: Peter Zijlstra Link: http://lkml.kernel.org/r/5028F431.6000306@intel.com Signed-off-by: Thomas Gleixner

sched/numa: Add SD_PERFER_SIBLING to CPU domain

2012-07-26T09:46:58Z

Commit 8e7fbcbc22c ("sched: Remove stale power aware scheduling remnants and dysfunctional knobs") removed SD_PERFER_SIBLING from the CPU domain. On NUMA machines this causes that load_balance() doesn't perfer LCPU in same physical CPU package. It causes some actual performance regressions on our NUMA machines from Core2 to NHM and SNB. Adding this domain flag again recovers the performance drop. This change doesn't have any bad impact on any of my benchmarks: specjbb, kbuild, fio, hackbench .. etc, on all my machines. Signed-off-by: Alex Shi Signed-off-by: Peter Zijlstra Link: http://lkml.kernel.org/r/1342765190-21540-1-git-send-email-alex.shi@intel.com Signed-off-by: Ingo Molnar

Merge branch 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2012-05-23T01:27:32Z

Pull scheduler changes from Ingo Molnar: "The biggest change is the cleanup/simplification of the load-balancer: instead of the current practice of architectures twiddling scheduler internal data structures and providing the scheduler domains in colorfully inconsistent ways, we now have generic scheduler code in kernel/sched/core.c:sched_init_numa() that looks at the architecture's node_distance() parameters and (while not fully trusting it) deducts a NUMA topology from it. This inevitably changes balancing behavior - hopefully for the better. There are various smaller optimizations, cleanups and fixlets as well" * 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: sched: Taint kernel with TAINT_WARN after sleep-in-atomic bug sched: Remove stale power aware scheduling remnants and dysfunctional knobs sched/debug: Fix printing large integers on 32-bit platforms sched/fair: Improve the ->group_imb logic sched/nohz: Fix rq->cpu_load[] calculations sched/numa: Don't scale the imbalance sched/fair: Revert sched-domain iteration breakage sched/x86: Rewrite set_cpu_sibling_map() sched/numa: Fix the new NUMA topology bits sched/numa: Rewrite the CONFIG_NUMA sched domain support sched/fair: Propagate 'struct lb_env' usage into find_busiest_group sched/fair: Add some serialization to the sched_domain load-balance walk sched/fair: Let minimally loaded cpu balance the group sched: Change rq->nr_running to unsigned int x86/numa: Check for nonsensical topologies on real hw as well x86/numa: Hard partition cpu topology masks on node boundaries x86/numa: Allow specifying node_distance() for numa=fake x86/sched: Make mwait_usable() heed to "idle=" kernel parameters properly sched: Update documentation and comments sched_rt: Avoid unnecessary dequeue and enqueue of pushable tasks in set_cpus_allowed_rt()